Harmonic　drive　is　an　indispensable　device　for　robotic　joint,　and　transmission　accuracy　of　harmonic　drive　is　one　of　its　most　important　performance　indexes.　Due　to　the　unsystematic　research　on　the　accuracy　of　harmonic　drive,　the　accuracy　consistency　of　harmonic　drive　is　poor,　and　the　prediction　accuracy　is　seriously　insufficient.　This　study　focuses　on　modeling　of　transmission　error　system　and　prediction　of　transmission　accuracy.　Through　tracing　analysis　of　transmission　error　of　harmonic　drive,　a　transmission　error　model　including　manufacturing,　assembly　and　tooth　profile　error　is　established.　Based　on　Rayleigh　distribution　of　error　sources　and　considering　multi-tooth　meshing　effect　of　harmonic　drive,　the　transmission　accuracy　prediction　model　is　built.　Tooth　profile　error　is　measured　by　gear　measuring　center,　dimension　error　and　geometric　tolerance　are　gauged　by　coordinate　measuring　machine.　The　transmission　accuracy　of　three　types　harmonic　drive　(SHG14,　SHG20　and　SHG25)　is　measured　by　harmonic　transmission　error　test　bench　under　rated　conditions.　The　comparison　results　show　that　the　difference　between　the　predicted　and　experimental　values　is　less　than　15%,　which　proves　the　validity　of　the　accuracy　prediction　model.　Prediction　method　play　a　crucial　role　for　accuracy　control　of　harmonic　drive　system.